Revving with no bar/chain on

[Nutball]

Maybe it's the high compression of modded saws that knock the clutches loose, though I had one out of 4 or 6 chinese 365's break a flywheel key during it's first run without a bar. I can't remember if I reved it or not, I think I did.

I took some advice long ago to use an impact driver for clutches, so much easier, you don't need a piston stopper and sometimes you don't even need a spark plug.

 

[Billy Currie]

After a saw build I will start it with out a bar and chain, but I also leave off the clutch and drum. I usually do this to set the idle mixture and allow the saw to get up to temperature and shut it down. I don't run it much at all at WOT at this point, just set the low speed and maybe see how the carburetor acts while transitioning off of idle.

I have seen a clutch come apart many years ago. Yes it hurt and no I never found all of the clutch.

 

[a. palmer jr.]

The clutch bearing is designed to control the clutch drum at idle as soon as you give the saw a rev the clutch shoes engage and the bearing is locked and no longer spinning.
Reving a saw WOT with no bar and chain and then letting off the trigger and shutting the saw off you will still hear the clutch drum spinning at about 20k for a min or two not really what that little bearing was designed for lol

Yes, the last time I revved up a saw (192T) without the bar and chain I had to go find my clutch, bearing, sprocket and even the oil pump worm gear....